<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        
        .imgList {
            width: 200px;
            height: 200px;
            margin: 10px auto;
            position: relative;
        }
        
        img {
            width: 200px;
            height: 200px;
        }
        
        .imgList li {
            position: absolute;
            list-style-type: none;
        }
        
        .imgList li:nth-child(2) {
            z-index: 1;
        }
        
        .pointer {
            position: absolute;
            z-index: 999;
            bottom: 10px;
            left: 20px;
        }
        
        .pointer a {
            width: 10px;
            height: 10px;
            background-color: rgba(255, 0, 0, .6);
            /* 边框后没有背景 */
            background-clip: content-box;
            border: 2px transparent solid;
            display: block;
            float: left;
            border-radius: 50%;
            margin-left: 5px;
        }
        
        .pointer a:hover {
            background-color: bfa;
            border: 2px black solid;
        }
    </style>
</head>

<body>
    <ul class="imgList">
        <li>
            <a href="javascript:;"><img src="./image/a.png" alt=""></a>
        </li>
        <li>
            <a href="javascript:;"><img src="./image/b.png" alt=""></a>
        </li>
        <li>
            <a href="javascript:;"><img src="./image/c.png" alt=""></a>
        </li>
        <div class="pointer">
            <a href="">
                <li></li>
            </a>
            <a href="">
                <li></li>
            </a>
            <a href="">
                <li></li>
            </a>
        </div>

    </ul>
</body>

</html>